I have actually had a very similar experience. I was bouldering in the clear cut at Gold Bar, goofing around in my approach shoes, slipped and my foot wedged between two very sharp rocks slicing my ankle into a gusher. No arteries were severed, and I did not need to be carried out thankfully, but it certainly solidified my stance that all climbing can be dangerous.
Luckily my friend had brought his first aid kit and was able to bandage me up pretty well.